Square Meter Calculator

Article — Square Meter Calculator

Square Meter Calculator: Area in m² for Four Common Shapes

A square meter calculator returns area in m² for the four shapes most floor plans, lots, and gardens reduce to: rectangle, triangle, circle, and trapezoid. 1 m² equals 10.7639 ft², 1.19599 yd², or 10,000 cm². A room 4 m by 5 m is 20 m² (215.3 ft²); a circular patio with a 3-metre radius covers 28.27 m² (304.3 ft²).

The square metre is the SI unit of area — the floor of a square one metre on each side. Outside the United States, it is the unit on every floor plan, every flooring quote, every real-estate listing. NIST and the BIPM both anchor the metre to the speed of light (defined value: 299,792,458 m/s), which is why metric areas reproduce exactly across countries.

What a square meter calculator does

A square meter calculator computes area for rectangles, triangles, circles, and trapezoids and reports the answer in m² alongside square feet, square yards, square inches, square centimetres, and hectares. Pick the shape, enter the dimensions in any of four units (m, cm, ft, in), and the calculator does the conversions in the background.

The four shapes cover most practical layouts. Rectangle handles standard rooms, lots, decks, and any wall section. Triangle covers roof gables, attic floor area, garden beds, and parts of L-shaped rooms. Circle covers patios, pools, and rotunda floors. Trapezoid covers sloped roofs, terraced gardens, and any space where two parallel edges differ in length.

Square meter formulas by shape

• Rectangle: A = l × w
• Triangle: A = ½ × b × h
• Circle: A = π × r² (π ≈ 3.14159265)
• Trapezoid: A = ½ × (b₁ + b₂) × h
• 1 m² = 10,000 cm² = 10.7639 ft² = 1.19599 yd²
• 1 hectare = 10,000 m² = 2.4711 acres

For triangle and trapezoid, “height” is the perpendicular distance from the base to the opposite vertex (triangle) or the perpendicular between the two parallel sides (trapezoid). Measuring the slope distance instead of the perpendicular is the most common source of error and produces a larger answer than reality.

Converting square meters and square feet

The conversion constant is 1 m² = 10.7639 ft². The number drops out of the linear definition: 1 m = 3.28084 ft, and 3.28084 squared is 10.7639. The reverse is 1 ft² = 0.092903 m², which is the squared version of 1 ft = 0.3048 m.

Square meters of typical rooms

Room size norms vary by country, but two patterns hold. European and Asian apartments measure 15-25% smaller than US equivalents at the same bedroom count. UK studio flats average 35-45 m²; a Tokyo studio is often 20-30 m². A typical American studio is 35-50 m² (380-540 ft²).

• Studio apartment = 25-50 m² (270-540 ft²)
• One-bedroom apartment = 45-70 m² (480-750 ft²)
• Two-bedroom apartment = 65-95 m² (700-1,020 ft²)
• Three-bedroom house = 110-160 m² (1,180-1,720 ft²)
• Master bedroom = 15-22 m² (160-240 ft²)
• Kitchen = 8-15 m² (86-160 ft²)

Square meters for flooring and paint

Flooring is sold by area in the unit the supplier uses: m² in most metric markets, ft² in the US. Standard practice is to add a waste factor — 5-10% for vinyl rolls and laminate, 10-15% for hardwood and ceramic tile, 15-20% for stone and pattern-matched material. For a 20 m² room with hardwood, order 22-23 m² of stock.

Wall paint coverage is roughly 12-14 m² per liter on smooth drywall for one coat, manufacturer-typical reference. A 50 m² room with 2.5 m ceilings has about 80 m² of wall area (perimeter × height − openings). At 13 m²/L that needs about 6.2 liters of paint per coat — round to two 4-liter cans for two-coat coverage with a margin.

Hectares, acres, square meters

Hectares are the metric land-area unit. One hectare is 10,000 m² — a square 100 metres on a side. It is large enough for farm parcels and small enough that municipal zoning records use it for residential lots. The older “are” (100 m²) survives mainly in real-estate listings in parts of central Europe.

Acres are the imperial counterpart. One acre is 43,560 ft², which is 4,046.86 m². So 1 hectare = 2.4711 acres, and 1 acre = 0.4047 hectares. Soccer pitches under FIFA standards are about 0.7 ha (1.7 acres); American football fields including end zones are about 0.535 ha (1.32 acres).

Measuring irregular areas in m²

Irregular shapes split into rectangles, triangles, and trapezoids. Walk the perimeter, sketch a rough plan, then draw straight lines that divide the space into rectangles wherever possible and triangles or trapezoids wherever a wall jogs. Compute each piece in the square meter calculator and add the answers.

For curved edges (a garden bed with a meandering border), approximate the curve with several trapezoids of varying height. Each trapezoid covers a slice of the curve, and the sum is close to the true area — usually within 1-2% if you cut the slice height fine enough.

Common square meter mistakes

Three recur. The first is measuring slope length instead of horizontal length on a sloped floor or roof — always project to the perpendicular. The second is mixing units; if length is in metres and width in centimetres, the answer is off by a factor of 100. The third is forgetting to halve the diameter when entering a circle dimension — the formula uses radius, and most measurements happen across the diameter.